(CNN) – Ukrainian interim Prime Minister Arseniy Yatsenyuk is coming to the U.S. and will meet with President Barack Obama on Wednesday, as upheaval in Ukraine has spiraled into an increasingly tense dispute between Russia and the West.

But it seems like Ukraine's Crimea is already lost, as former defense secretary Robert Gates told Fox News Sunday; Russian President Vladimir Putin is likely not going to withdraw Russian troops from there the southern peninsula.

So what is the end game now?

"It's a little bit too negative to say that Crimea is lost," said president of the Council on Foreign Relations Richard Haass. "We've got to give it a little more time. For all we know, Russians are going to feel the effects of the sanctions, of some of their diplomatic isolation."

But, adds Haass, "there's got to be a lot of emphasis, if you will, on Plan B, which is ... to try to prevent the situation from deteriorating, which essentially would mean discouraging the Russians from any way extending their position inside the country."FULL POST

(CNN) – There are many theories, including terrorism, about what could have happened to missing Malaysian Airlines Flight 370, which disappeared en route to Beijing Saturday. Days later, there is still no sign of the plane.

"Everything has to be considered a possibility right now," said Rep. Peter King, R-New York, member of the Homeland Security and Intelligence committees.FULL POST

(CNN) – Malaysia Airlines Flight 370 took off from Kuala Lumpur shortly before 1 a.m. Saturday (1 p.m. Friday ET). The Boeing 777-200ER, carrying 227 passengers and 12 crew members, went missing while flying to Beijing. Days later, there is still no sign of the missing plane.

"The FBI has to presume that it's terrorism, and do the types of things to conduct a preliminary investigation," said former FBI Assistant Director James Kallstrom conducted the criminal investigation into TWA flight 800, which exploded shortly after take-off from JFK in 1996.

"It's very, very active. It's complex now. You're talking about two or three different countries. They don't know where the plane is. The radar coverage is sketchy, at best. And they are looking in the water but they should also probably look on land in Vietnam," said Kallstrom.FULL POST

(CNN) – For the first time, there is some insight into Sandy Hook gunman Adam Lanza's deteriorating mental state, and the warning signs that led up to the massacre of 26 children and teachers, from one of the people who knew the intimate details of Adam's struggles – his father Peter.

"He felt having been hounded for his story, that perhaps telling it could be helpful to the families who had lost children at Sandy Hook," Solomon said in an interview with CNN's "The Lead with Jake Tapper."FULL POST

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The Lead with Jake Tapper draws not only on Tapper’s deep knowledge of politics and national issues, but also seeks to examine and advance stories across a wide range of topics that demonstrate his own curiosities and interests. Compelling headlines come from around the country and the globe, from politics to money, sports to popular culture, based on news drivers of the day.